title: Can regional anesthesia and analgesia prolong cancer survival after orthopaedic oncologic surgery?
abstract: BACKGROUND
  The perioperative period of major oncologic surgery is characterized by immunosuppression, angiogenesis, and an increased load of circulating malignant cells. It is a window period in which cancer cells may seed, invade, and proliferate. Thus, it has been hypothesized that the use of regional anesthesia with the goal of reducing surgical stress and opioid and volatile anesthetic consumption would avoid perioperative immune suppression and angiogenesis and ultimately cancer recurrence.
  
  
  OBJECTIVE
  We performed a systematic review of the literature on the use of regional anesthesia and postoperative analgesia to improve cancer-related survival after oncologic surgery. Our primary topic of interest is survival after orthopaedic oncologic surgery, but because that literature is limited, we also have systematically reviewed the question of survival after breast, gastrointestinal, and genitourologic cancers.
  
  
  METHODS
  We searched the PubMed and Embase databases with the search terms: "anesthesia and analgesia", "local neoplasm recurrence", "cancer recurrence", "loco-regional neoplasm recurrence", "disease-free survival", and "cumulative survival rates". Our initial search of the two databases provided 836 studies of which 693 were rejected. Of the remaining 143 studies, only 13 articles qualified for inclusion in this systematic review, based on defined inclusion criteria. All these studies had retrospective design. Due to the high heterogeneity among the identified studies and the complete absence of randomized controlled trials from the literature on this topic, the results of a meta-analysis would be heavily confounded; hence, we instead performed a systematic review of the literature.
  
  
  RESULTS
  No eligible studies addressed the question of whether regional anesthesia and analgesia have an impact on survival after musculoskeletal cancer surgery. Only one relevant clinical study was identified on regional breast cancer survival; it suggested a benefit. The literature on gastrointestinal and genitourinary surgery was larger but mixed, although some preliminary studies do suggest a benefit of regional anesthesia on survival after oncologic surgery in those patient populations.
  
  
  CONCLUSIONS
  Although basic science studies suggest a potential benefit of regional anesthesia and stress response reduction in cancer formation, we found little clinical evidence to support the theory that regional anesthesia and analgesia improve overall patient survival after oncologic surgery.
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, The University of Texas-MD Anderson Cancer Center, 1515 Holcombe Blvd, Box FC13, Houston, TX, 77030, USA, jcata@mdanderson.org.
authors.forename: Juan P
authors.initials: JP
authors.lastname: Cata
authors.forename: Mike
authors.initials: M
authors.lastname: Hernandez
authors.forename: Valerae O
authors.initials: VO
authors.lastname: Lewis
authors.forename: Andrea
authors.initials: A
authors.lastname: Kurz
mesh_terms: D000698:Analgesia / Q000009:adverse effects / Q000401:mortality; D000765:Anesthesia, Conduction / Q000009:adverse effects / Q000401:mortality; D018450:Disease Progression; D018572:Disease-Free Survival; D006801:Humans; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000517:prevention & control*; D009369:Neoplasms / Q000276:immunology / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D010149:Postoperative Pain / Q000209:etiology / Q000517:prevention & control*; D012307:Risk Factors; D013312:Stress, Physiological; D013514:Surgical Procedures, Operative / Q000009:adverse effects / Q000401:mortality; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome